Method of preparing foldable hydrophilic ophthalmic device materials

Abstract

Foldable, hydrophilic, ophthalmic device materials are cured by exposure to blue light using a benzoylphosphine oxide photoinitiator.

We claim: 
     
       1. A method of preparing a foldable, acrylic, high refractive index ophthalmic material comprising the steps of: a) preparing a device-forming mixture comprising a benzoylphosphine oxide photoinitiator, an UV-absorbing chromophore and one or more hydrophilic device-forming monomers selected from the group consisting of: 2-hydroxyethylmethacrylate; 2-hydroxyethylacrylate; N-vinylpyrrolidone; glyceryl methacrylate; glyceryl acrylate; polyethylene oxide mono and dimethacrylates; and polyethylene oxide mono- and diacrylates; and   b) exposing the mixture to a blue-light source for a period of time sufficient to cure the device forming mixture.   
     
     
       2. The method of claim 1 wherein the hydrophilic monomer is selected from the group consisting of: 2-hydroxyethylmethacrylate and N-vinylpyrrolidone. 
     
     
       3. The method of claim 1 wherein the device material has a glass transition temperature no greater than 25° C. and an elongation of at least 150%. 
     
     
       4. The method of claim 1 wherein the total amount of hydrophilic monomer present in the device-forming mixture is at least 50% (w/w). 
     
     
       5. The method of claim 4 wherein the total amount of hydrophilic monomer present in the device-forming mixture is at least 70% (w/w). 
     
     
       6. The method of claim 5 wherein the total amount of hydrophilic monomer present in the device-forming mixture is at least 80% (w/w). 
     
     
       7. The method of claim 1 wherein the device forming mixture further comprises one or more additional device-forming monomers selected from the group consisting of: acrylic acid; C 1  -C 8  arylalkylacrylates; C 1  -C 8  alkylacrylates; C 1  -C 8  cycloalkylacrylates; N-alkylacrylamides (where alkyl=C 1  -C 4 ); phenoxyalkylacrylates (where alkyl=C 1  -C 8 ); and their corresponding methacrylates. 
     
     
       8. The method of claim 7 wherein the total amount of additional device forming monomer is 45% (w/w) or less. 
     
     
       9. The method of claim 1 wherein the benzoylphosphine oxide initiator is selected from the group consisting of: 2,4,6-trimethyl-benzoyldiphenylophosphine oxide; bis-(2,6-dichlorobenzoyl)-4-N-propylphenyl-phosphine oxide; and bis-(2,6-dichlorobenzoyl)-4-N-butylphenylphosphine oxide. 
     
     
       10. The method of claim 9 wherein the benzoylphosphine oxide initiator is 2,4,6-trimethyl-benzoyldiphenylphosphine oxide. 
     
     
       11. The method of claim 1 wherein the amount of benzoylphosphine oxide initiator is less than about 3% (w/w). 
     
     
       12. The method of claim 1 wherein the amount of benzoylphosphine oxide initiator is about 1% (w/w). 
     
     
       13. The method of claim 1 wherein the device forming mixture further comprises one or more ingredients selected from the group consisting of copolymerizable cross-linking monomers and blue-light absorbing chromophores. 
     
     
       14. The method of claim 1 wherein the blue-light source has an intensity of from about 1 to about 40 mW/cm 2  and the period of time in which the device forming mixture is exposed to the blue-light source is from about 5 minutes to about 4 hours. 
     
     
       15. The method of claim 14 wherein the bluelight source has an intensity of from about 10 to about 15 mW/cm 2 .